Managed to solve this... definitely not a standard solution but here we go.

Essentially by having a htmlhelper extension that gets the client resources and directly removes the EpiServerForm script src as below. This replaces the  Html.RequiredClientResources call.

		public static MvcHtmlString CustomRequiredClientResources(this HtmlHelper htmlHelper, string renderingArea)
		{
			var requiredResources =
				htmlHelper
					.RequiredClientResources(renderingArea)
					.ToString()
					.Replace(
						ModuleHelper.GetWebResourceUrl(typeof(FormContainerBlockController), ConstantsForms.StaticResource.JS.EPiServerFormsMinifyPath),
						string.Empty);

			return new MvcHtmlString(requiredResources);
		}

And then in a custom form container block you can get the script yourself and pass it through on a timer.

    <%
        var epiformsScriptPath = ModuleHelper.GetWebResourceUrl(typeof(FormContainerBlockController), ConstantsForms.StaticResource.JS.EPiServerFormsMinifyPath);
    %>
		<script type="text/javascript">

			function reloadepiFormJs(url) {
				var theScript = document.createElement('script');
				theScript.src = url;
				document.head.appendChild(theScript);
			}

			window.setTimeout(function()
			{
				reloadepiFormJs('<%: epiformsScriptPath %>');
			}, 3000);
		</script>

 If anyone has any feedback on a better way to solve this I'm all ears. :)

This same issue showed up for us. 

@Ben did you find a better way to resolve it?

We used Laurence's approach. 

This approach no longer works in CMS 12. GetWebResourceUrl internal method signature has changed and I cannot get webresource url from this method as it returns in CMS 11.

@Levon

Is the original EPiServerForms.js resource reference being rendered in your version? I don't see the resource in the list with the call to Html.RequiredClientResource, and so the builtin reference to EPiServerForms.js is missing for me.

If that's the same for you you should be able to replace the call to 

ModuleHelper.GetWebResourceUrl

with a simple reference to /util/EPiServer.Forms/EPiServerForms.js or wherever it is in your site.